Add coingecko mapping for THOR token on Avalanche

[onyb]

Summary

Disambiguate between Thor on Avalanche vs Thorswap on Ethereum

Internal discussions	Slack

Type of change ( select one )

• Product feature
• Bug fix
• Performance improvement
• Refactor
• Other

Resolves brave/brave-browser#22651.

Tested Environments

• Development
• Staging
• Production

Before submitting this PR:

• Does your code build cleanly without any errors or warnings?
• Have you used auto closing keywords?
• Have you added tests for new functionality?
• Have validated query efficiency for new database queries?
• Have documented new functionality in README or in comments?
• Have you squashed all intermediate commits?
• Is there a clear title that explains what the PR does?
• Have you used intuitive function, variable and other naming?
• Have you requested security / privacy review if needed
• Have you performed a self review of this PR?

Manual Test Plan:

https://ratios.rewards.brave.com/v2/relative/provider/coingecko/thor/usd/1d should return Thor (Avalanche) price and not Thorswap (Ethereum) price.

[nvonpentz]

Tested on dev

$ curl https://ratios.rewards.brave.software/v2/relative/provider/coingecko/thor/usd/1d

{"payload":{"thor":{"usd":7.14,"usd_timeframe_change":10.820245398520598}},"lastUpdated":"2022-05-10T17:33:07.834056155Z"}

[husobee]

#1420 so we can get ci to pass